Silicon is an important constituent of which of the following?

Which of the following statements is correct?

In the following reaction,identify the nature of the product formed by the complete hydrolysis of the underlined atom at $R.T.$:
$\underline{P}OCl_3 + H_2O \longrightarrow H_3PO_4 + HCl$

Which one of the following phosphorus halides contains both tetrahedral and octahedral shaped ions in its solid state?

The order of catenation power is $Ge < Si < C$. What are the $C-C$,$Si-Si$,and $Ge-Ge$ bond energies (in $kJ/mol$) respectively?

Which one of the following elements reacts with steam?